Amplitude-only optimizing method of multi-subaperture multi-beam antenna for SAR applications

An amplitude-only optimizing method is presented to synthesize the multiple beams of an array antenna for multi-mode SAR application, including stripmap mode, DPCA (Displaced Phase Centers Multi-beam in Azimuth) mode, etc. The array antenna is required to work with the whole aperture or several subapertures in azimuth simultaneously. With an iterative solution scheme of improved projection matrix algorithm (PMA), the amplitude excitations are determined and the sidelobe levels of the beams are controlled. Meanwhile, Taylor-based synthesis method and differential evolution algorithm with global and local neighborhoods (DEGL) are also used to synthesize the beams of the array antenna. With a sample application of multi-beam array antenna design, the effectiveness of amplitude-only PMA is validated and its efficiency is better than the later two methods.